1. Technical Field
A method for forming a wire in a semiconductor device is disclosed. More particularly, a method for forming a wire in a semiconductor device is disclosed, wherein in forming a titanium film and a titanium nitride film as a barrier metal layer, a titanium film and a titanium nitride film are each deposited in different chambers by first removing a titanium oxide film that is used as an insulating film. The titanium oxide film is generated by allowing the upper titanium portion of the titanium film to bond with oxygen in air as the upper portion of a titanium film is exposed to air by a plasma process. A titanium nitride film is then deposited on the underlying non-oxidated titanium film. The disclosed methods reduce the throughput time of each chamber even in the case where one chamber breaks down.
2. Description of the Related Art
Generally, in the method for fabricating a semiconductor device, on condition that a metal wire serving as a conductive line between upper and lower portions is formed in a multi-layer, an inter-layer insulating film for insulating the multi-layer is widely used. A contact hole is formed by stacking a photoresist film on the upper part of the inter-layer insulating film to have a contact hole forming portion and etching the portion, and a metal wire is formed by immersing a metal layer into the contact hole.
Such a metal line is used as a bit line and a word line to electrically connect a gate electrode, a capacitor, etc. vertically and horizontally, for thereby constructing a semiconductor device.
FIG. 1 is a view illustrating a state in which a thermal treatment is conducted for a wire formed by a conventional method for forming a wire in a semiconductor device. As illustrated in FIG. 1, a conductive layer and a dielectric layer are sequentially formed on a semiconductor substrate having a predetermined substructure, and then a photoresist film is coated for forming a contact hole on an upper portion of the dielectric layer.
Then, the contact hole is formed in the dielectric layer by etching the dielectric layer using the photoresist film as a mask, and thereafter a barrier metal layer constructed as a double layer is formed by sequentially depositing titanium used as a first barrier metal layer and a titanium nitride film used as a second barrier metal layer on the dielectric layer on which the contact hole is formed.
At this time, after depositing the titanium used as the first barrier metal layer, the first and second barrier metal layers are sequentially and continuously deposited in ultra high vacuum in the event that the titanium is exposed to air in order to prevent the formation of a titanium oxide film used an insulating film on the titanium layer.
Continually, tungsten is deposited on the second barrier metal layer by using a chemical vapor deposition method, and thereafter a tungsten plug is formed by performing a chemical mechanical polishing process.
In the above-described conventional method for forming a wire in a semiconductor device, after depositing the titanium used as the first barrier metal layer, it is necessary to use cluster of equipment consisting of multi-chambers in ultra high vacuum continuously depositing the first and second barrier metal layers in the event that the titanium is exposed to air in order to prevent the formation of the titanium oxide film used as the insulating film on the titanium layer.
However, the cluster of equipment consisting of multi-chambers in ultra high vacuum is very expensive and the construction of the cluster of equipment is made complex due to the vacuum equipment. In addition, the cluster of equipment consisting of multi-chambers has a low throughput or high throughput time due to periodic breakdowns.
Therefore, a method for forming a wire in a semiconductor device is disclosed, wherein, in forming a titanium film and a titanium nitride film as a barrier metal layer, the titanium film and a titanium nitride film are deposited in different chambers by removing a titanium oxide film used as an insulating film that is generated by an upper titanium portion of a titanium layer bonding with oxygen in air as the upper portion of the titanium film is exposed to air by a plasma process and then depositing a titanium nitride film on the underlying titanium film. The disclosed method can reduce the throughput time of chamber equipment since a partial utilization of the system of the chamber equipment is enabled by utilizing one chamber in case another chamber breaks down.
A disclosed method for forming a wire of a semiconductor device comprises: forming a portion for forming a contact hole by coating a photoresist film after depositing sequentially a conductive layer and a dielectric layer on a semiconductor substrate having a predetermined lower structure; forming a contact hole through a contact hole etching process by using the photoresist film as a mask; performing a heat process after depositing a first barrier metal layer on the entire surface of the dielectric layer formed the contact hole; depositing a second barrier metal layer after removing an insulation film formed on the upper portion of the first barrier metal layer by performing a plasma treatment process; forming a tungsten plug by performing a chemical mechanical polishing process after depositing tungsten on the second barrier metal layer.
Preferably, after removing an insulation layer on the first barrier metal layer by the plasma process, when depositing a second barrier metal layer on the first barrier metal removed the insulation layer, the second barrier metal layer is deposited to a thickness of about 50 xc3x85 by conducting the thermochemical vapor deposition process. Thereafter, the resistivity is reduced by removing the impurities in the second barrier metal layer by a plasma treatment.
Also, preferably, the second barrier metal layer is deposited to a desired deposition thickness by repeating the thermochemical vapor deposition process and the plasma treatment.